1. Field of the Invention
The present invention relates to a recording and reproducing apparatus for recording and reproducing digital data.
2. Description of the Prior Art
A digital VCR (video cassette recorder) for digitizing and compressing pictures and sounds, and recording helically in a magnetic tape is already put in practical use at the present. In the digital VCR, track error correction is done by double error correction in a track. To record digital data by using the digital VCR, it is necessary to keep a sufficiently low error rate. In pictures, an error can be concealed, the error will not propagate, but in computer data, by contrast, errors are not allowable in most cases. Besides, in recording of video signals compressed in a technique for causing error propagations widely, it is required to keep a low error rate. In the existing recording apparatus, however, an error rate is too high for recording computer data or video signals causing error propagations. Another problem was that the correction capacity for burst error for correcting error in the track was low.
Other apparatus is known to record digital data by using DAT (digital audio tape) which is audio recording apparatus for consumer use such as DDS. In this apparatus, in addition to the double error correction in the track, error correction coding is also carried out between tracks. A codeword for inter-track error correction coding used in DDS is composed of a symbol of a same address among plural tracks. Generally, the code of high error correction capacity has a long codeword length, and by employing this method, its correction unit becomes longer along with the correction capacity. In a case of recording and reproducing apparatus using the digital VCR, the capacity per track is large, and to increase the correction unit, capacity of a memory of correction circuit or the like must be increased, and such increase of circuit scale causes a problem.
In the digital VCR, data to be recorded comprises video data, audio data, and auxiliary data for controlling the video data and the audio data. These data are recorded on a magnetic tape by the double error correction coding, and in this case since the auxiliary data records the information about the recorded data, it is desired to record the auxiliary data in the same position as the digital VCR also in the digital data recording and reproducing apparatus.
Furthermore, there is a track for recording only parity. At this time, data of trick play or the like cannot be continuously disposed at a specific position on the track.
A track composition in a conventional digital VCR is shown in FIG. 10. In the conventional digital VCR, the video data are processed by inner error correction coding, and recorded in a video data region 73, a video outer parity generated by outer error correction coding of the video data and the auxiliary data is recorded in a video outer parity region 75, the audio data are processed by inner error correction coding and recorded in an audio data region 70, an audio outer parity generated by outer error correction of the audio data is recorded in an audio outer parity region 71, and the auxiliary data is recorded in a first auxiliary data region 72 and a second auxiliary data region 74.